Mastermind
by Joe Genaro

Effect

You show 4 metal tubes - spectator handles tubes - each spectator keeps one of the tubes and one is given to you. They are unmarked and identical in every way. You take a $100 dollar bill (or any valuable or trinket that can fit in the tube) and put it inside the metal tube, cap it and hand it to one of the spectators. Turn your back (or leave the room) and instruct spectators to cap their tubes and mix them up. The spectators then place the metal tubes inside the larger black plastic tubes. While your back is still turned, inform the spectators that they may switch tubes with one another before putting them in the tube holder. In other words, there is just no way you can possibly know which tube contains the treasure - but you do, instantly!!!